Conventional casting methods such as die casting, gravity permanent mold casting, and squeeze casting have long been used for Aluminum-Silicon (Al—Si) alloys. However, where semi-solid metal (SSM) casting of Al—Si alloy materials has been involved, the conventional methods have not been employed successfully to date. Rheocasting and thixocasting are casting methods that were developed in an attempt to convert conventional casting means to SSM casting. However, these SSM methods require additional retrofitting to conventional casting machinery and challenges remain in the ability to manipulate the microstructures of primary Al and/or Si in the cast part for improving cast performance.
Accordingly, it is desirable to provide a method of casting SSM hypereutectic Al—Si alloys utilizing both conventional and rheocasting means that can impart desirable mechanical properties. In particular, there is a need for a process to control the nucleation and growth of primary Si particles in hypereutectic Al—Si alloys. Further still, it is desirable to provide a method of producing products with Al—Si alloy castings by conventional or rheocasting techniques wherein the temperature of the semi-solid slurry can be controlled.